Effective Reversible Information Hiding Based on Block Priority of JPEG Images

Due to the redundancy information of the JPEG image is less than the uncompressed ones, it is difficult to obtain high embedding capacity for hiding the secret information into JPEG images. Meanwhile, after embedding the secret information, the size of the JPEG image is significantly increased, which leads to the problems that the secret information is easily perceived and the image storage space is significantly increased. Aiming at the above problems, this paper proposes a reversible information algorithm based on the block priority of JPEG images. In the algorithm, the AC coefficients are firstly divided into three classes based on analyzing the visual characteristics, coding styles and DCT coefficient distribution of the JPEG images. Then, according to the distribution of three kinds of AC coefficients in the 8x8 sub-blocks, the priorities of blocks used to embed the secret information are decided. Lastly, the selected blocks are sequentially embedded with secret information according to their priorities. The experimental results have shown that, compared with the existing reversible algorithms, the proposed algorithm can effectively increase the embedded information capacity and restrain the size of the image after embedding secret information in the premise of guaranteeing the visual quality of the image.